Stretchable OLED Encapsulation via Polymer Dot Lattices

Solution Overview

Problem

Conventional stretchable electronic displays are prone to cracking when bent or stretched due to brittle inorganic materials in the encapsulation layer, leading to moisture ingress and visual defects, and existing encapsulation techniques fail to provide sufficient flexibility and durability.

Innovation Solution

A thin-film encapsulation layer comprising polymer dots or lattices interspersed with conformal dielectric layers, which can splay outward and compress to accommodate bending or stretching, reducing the risk of cracking and enhancing durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inorganic materials are used in the encapsulation layer, then the encapsulation provides a robust barrier against moisture and oxidants, but the encapsulation layer becomes brittle and prone to cracking when bent or stretched

Engineering Contradiction:

Improvebarrier protectionVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The encapsulation layer is constructed as a composite structure combining inorganic dielectric layers (such as aluminum oxide, silicon oxide, or silicon nitride) with organic polymer layers (such as cycloolefin copolymer or polyimide). This composite structure allows the inorganic layers to provide moisture and oxidant barrier protection while the organic polymer layers provide flexibility and crack resistance, enabling the encapsulation to withstand bending and stretching without failure.

Inventive Principle:

Principle #40Composite materials

2Strength

If the encapsulation layer is made flexible using polymer materials, then the display can be bent or stretched, but the barrier protection against moisture and oxidants is insufficient

Engineering Contradiction:

ImproveflexibilityVSAvoidbarrier protection

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The encapsulation layer is constructed as a composite structure combining inorganic dielectric layers (such as aluminum oxide, silicon oxide, or silicon nitride) with organic polymer layers (such as cycloolefin copolymer or polyimide). This composite structure allows the inorganic layers to provide moisture and oxidant barrier protection while the organic polymer layers provide flexibility and crack resistance, enabling the encapsulation to withstand bending and stretching without failure.

Inventive Principle:

Principle #40Composite materials

3Reliability

If multiple encapsulation layers are stacked to improve barrier protection, then the barrier against moisture and oxidants is enhanced, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvebarrier protectionVSAvoidencapsulation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulation layer is divided into multiple alternating inorganic and organic sub-layers, where each inorganic layer provides barrier protection and each organic layer provides flexibility. This segmented multi-layer structure achieves enhanced barrier protection through the stacked inorganic layers while the interspersed organic layers maintain overall flexibility and reduce manufacturing complexity by distributing stress across multiple compliant interfaces.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The encapsulation layer provides increased flexibility and durability, allowing electronic displays to be bent or stretched without significant damage, while maintaining a robust barrier against moisture and oxidants, thus extending display lifetime and improving picture quality.

Implementation Method 1

a first dielectric layer conformally covering the plurality of first polymer projections and any exposed underlying surface in the spaces between the first polymer projections

Methodology Applied

Scientific EffectConformal deposition: Deposition (physical)

Data Source

PatentUS11258045B2Methods of forming stretchable encapsulation for electronic displays

Publication Date: 2022.02.22 APPLIED MATERIALS INC

AI summary

A method of encapsulating an organic light-emitting diode display includes depositing a plurality of first polymer projections onto a light-emitting side of a display layer having a plurality of organic light-emitting diodes (OLEDs) such that the plurality of first polymer projections have spaces therebetween that expose an underlying surface, and conformally coating the first polymer projections and the spaces between the first polymer projections with a first dielectric layer such that the first dielectric layer has side walls along sides of the first polymer projections and defines wells in spaces between the side walls.